Well hello, April!

Welcome. Nice Camaro!
I'd look to hotchkis for some larger diameter sway bars, subframe connectors and stiffer springs to start with, then move on to the brakes. Baer has a few packages that would be a huge upgrade from stock for you.
My first choice for engine mods would be to swap in a 350 and do the typical mods. Headers, intake/throttle body, then move on to a cam swap and higher flowing heads.
If you're limited to keeping the 305, the same mods apply, but don't expect huge power gains.